Skip to main content

Standards Updates: NSF/ANSI 40, NSF/ANSI 245, NSF/ANSI 350, and NSF/ANSI 41

New versions of wastewater standards NSF/ANSI 40, NSF/ANSI 245, NSF/ANSI 350, and NSF/ANSI 41 have been published - find out more below.
Unless otherwise noted, all changes have been implemented immediately by NSF.

The 2022 Version of NSF/ANSI/CAN 40 Includes the Following Changes:

Issue 42

This revision updated language regarding odor and color in Section 8.4.2.4.

Issue 43

This revision updates language in Sections 6.1, 6.2.2, and Annex I-2 to bring it in line with NSF’s publishing guidelines. It also removes the word “NOTE” from Section 8.5.1.2 to make it clear that the language is a requirement of the standard.

Issue 44

This revision incorporates clarifications into Section 8 regarding influent wastewater characteristics that previously existed in an interpretation request.

Issue 45

This revision adds Normative Annex 1: Approval of scaling and alternate system configurations to provide guidance on scale up.

Issue 46

This revision adds language regarding effluent pH in Section 8.5.2.1.3. The language requires NSF 40 tests meet an average pH range for influent and effluent.

Issue 47

This revision updates language in Section 5.8 to harmonize the audible and visual alarm requirements between NSF/ANSI 40, NSF/ANSI 245, and NSF/ANSI 350.

Issue 48

This revision updated the normative references in Section 2.

Issue 50

This revision removes the definitions from the Wastewater Technology suite of standards and instead references the newly adopted NSF/ANSI 437: Glossary of Wastewater Technology Terminology.

Issue 52

This revision modifies language in Section 8.2.2.2 to harmonize stress loading language among the suite of Wastewater Standards. The new language requires that stress loading events are performed in the order specified in the standard and adds a week tolerance to when stress loading sequences begin. This change will have a deadline for compliance of January 1, 2024.

The 2022 Version of NSF/ANSI/CAN 245 Includes the Following Changes:

Issue 26

This revision updates the normative references in Section 2.

Issue 28

This revision clarifies language regarding the pass/fail criteria for nitrogen removal in Section 8.4.3.3.

Issue 29

This revision updates language in Section 5.8 to harmonize the audible and visual alarm requirements between NSF/ANSI 40, NSF/ANSI 245, and NSF/ANSI 350.

Issue 30

This revision further updates the normative references in Section 2.

Issue 31

This revision removes the definitions from the Wastewater Technology suite of standards and instead references the newly adopted NSF/ANSI 437: Glossary of Wastewater Technology Terminology.

Issue 33

This revision modifies language in Section 8.2.2.2 to harmonize stress loading language among the suite of Wastewater Standards. The new language requires that stress loading events are performed in the order specified in the standard and adds a week tolerance to when stress loading sequences begin. This change will have a deadline for compliance of January 1, 2024.

The 2022 Version of NSF/ANSI/CAN 350 Includes the Following Changes:

Issue 57

This revision adds a noise correction chart to Section 5.4.

Issue 58

This revision updates the requirements for bypass alarms in Section 5.8. The language removes the requirement for a bypass alarm on systems that divert surplus water to a bypass as part of normal operation.

Issue 59

This revision modifies timing for grab samples in NSF/ANSI 350, adding an option to collect grab samples during morning or noon dosing period for gravity flow systems under Section 8.4.3.

Issue 61

This revision updates language in Section 8.1.2.2.1.1 to add clarity regarding combined Class C and Class R system testing based on a submitted interpretation request.

Issue 62

This revision adds clarity to Table N-1.1 by replacing dashes within some of the cells with “NA”.

Issue 65

This revision updates language regarding color, odor, oil film, and foam in Sections 8.5 and 8.6 in order to harmonize these sections with their counterpart sections in NSF/ANSI 40.

Issue 66

This revision updates Tables N-1.1 and N-1.2 to remove analyses that have been removed from the requirements of the standard.

Issue 67

This revision adds references for Sections 8.2.1.8 and 8.5.2 in Section 5.11 to add additional clarity to the language.

Issue 68

This revision updates language in Section 5.8 to harmonize the audible and visual alarm requirements between NSF/ANSI 40, NSF/ANSI 245, and NSF/ANSI 350.

Issue 69

This revision removes the requirement in Section 1.2 for systems certifying to NSF/ANSI 350 to also meet the requirements of NSF/ANSI 40, and removes the latter as a normative reference.

Issue 70

This revision affirms the addition of language allowing disinfection devices such as tablet or liquid chlorinators to be periodically refilled with disinfectant during testing in NSF/ANSI 350.

Issue 71

This revision removes the definitions from the Wastewater Technology suite of standards and instead references the newly adopted NSF/ANSI 437: Glossary of Wastewater Technology Terminology.

Issue 72

This revision updates normative references in NSF/ANSI 350.

Issue 74

This revision revises a section heading in Section 5.10 of NSF/ANSI 350.

Issue 75

This revision modifies language in Section 8.2.2.2 to harmonize stress loading language among the suite of Wastewater standards. The new language requires that stress loading events are performed in the order specified in the standard and adds a week tolerance to when stress loading sequences begin. This change will have a deadline for compliance of January 1, 2024.

The 2022 Version of NSF/ANSI/CAN 41 Includes the Following Changes:

Issue 11

This revision adds language regarding commercial applications to address systems installed in commercial settings such as office buildings.

Questions

For questions on this, contact our Standards department, or if you are an existing NSF customer, reach out to your account manager.

Onsite Wastewater Systems Testing

Work with NSF’s experts to assure public health officials of your product’s safety performance. In addition to boosting the confidence of your customers, NSF testing and certification services ensure broad market access in the onsite wastewater treatment industry.

How NSF Can Help You

Get in touch to find out how we can help you and your business thrive.

What’s New with NSF

  • NSF Launches Independent Certification Standard for Compact Products

    August 25, 2026
    New third-party certification verifies products cutting materials and shipping impacts while maintaining safety and performance.
    Read the Story
  • CELSIUS® Products Earn NSF Certified for Sport® Certification

    August 20, 2026
    CELSIUS® has earned NSF Certified for Sport® certification for select products, including the CELSIUS VIBES line, reinforcing the brand’s commitment to quality, transparency and consumer trust.
    Read the Story
  • Thomas Vyles Honored With 2026 Walter F. Snyder Environmental Health Award

    August 19, 2026
    The award honors Walter F. Snyder, co-founder and first executive director of NSF, and pioneers whose work advances environmental and public health.
    Read the Story
  • NSF Hosts First External Review Panel for ‘NSF/KWTC 555’ with Key Asian Water Authorities

    August 3, 2026
    Joint standard development gains momentum to enhance confidence in Asia’s water industry and advance drinking water safety.
    Read the Story